RATE COEFFICIENTS FOR FREE-RADICAL POLYMERIZATION OF BUTYL ACRYLATE TO HIGH CONVERSION

The free-radical polymerization of butyl acrylate is studied between 2 5-degrees-C and 80-degrees-C at pressures up to 2500 bar. The reaction is measured by applying excimer laser techniques in conjunction with time-resolved high-pressure near infrared spectroscopy. Rate coefficie nts of propagation, k(p), and termination, k(t), are obtained for an e xtended temperature, pressure, and conversion range. The dependence of k(t) on conversion is analyzed by means of a kinetic model which cons iders segmental diffusion, translational diffusion, and reaction diffu sion. It turns out that free-radical termination is essentially determ ined by reaction diffusion.